Hi all, I have dataset consiting of a response Y which is bivariate and 200 variables. I run an OPLS-DA and things looks fine. I wanted to run permuation test but using the code provide in the document ("ropls: PCA, PLS(-DA) and OPLS(-DA) for multivariate analysis and feature selection of omics data, Etienne A. Th?evenot, January 24, 2016") I couldn't understand it and apply it to my data.

set.seed(123)
obsI <- 20
featVi <- c(2, 20, 200)
featMaxI <- max(featVi)
xRandMN <- matrix(runif(obsI * featMaxI), nrow = obsI)
yRandVn <- sample(c(rep(0, obsI / 2), rep(1, obsI / 2)))
 layout(matrix(1:4, nrow = 2, byrow = TRUE))
for(featI in featVi) {
randPlsi <- opls(xRandMN[, 1:featI], yRandVn, predI = 2,
permI = ifelse(featI == featMaxI, 100, 0),
 plotL = FALSE)
plot(randPlsi, typeVc = "x-score", parDevNewL = FALSE,
 parCexN = 1.3, parTitleL = FALSE)
 mtext(featI/obsI, font = 2, line = 2)
if(featI == featMaxI)
 plot(randPlsi, typeVc = "permutation", parDevNewL = FALSE,
 parCexN = 1.3)
 }
mtext(" obs./feat. ratio:", adj = 0, at = 0, font = 2, line = -2, outer = TRUE)

I couldn't see where is the sampling from the response and from the variables. Would you plaese help in this or suggest any other method for permuation test.

Thanks